MAPI

Overview

The MAPI action hands a mail to a mail program installed on this PC. The mail goes out through the account set up there and lands in its Sent folder. You can display it before sending, send it directly or save it as a draft.

Client	Meaning
Default	the Windows default mail program (default)
Outlook	classic Outlook, with all options on this page
a name	a specific mail program, e.g. Thunderbird, eM Client or Team (Tobit David), as registered in Windows – 64- or 32-bit

In the diagram view of the workflow editor the action has a form. Send with lists the mail programs installed on this PC, with 32- or 64-bit; after installing one, the button next to it looks again. Under Other you type a name or a placeholder such as {{InitialData.MailProgram}}. What happens sets Mode: Open to check, Send directly or Save as draft (Outlook only). In the Mail section the Signature sits right below the text. Everything else is under More options; parameters the form does not know are kept under Other parameters as JSON.

Mode	Effect
Display	The mail opens in the mail program. You check it and send it yourself. (default)
Send	The mail is sent without opening a window. Needs at least one recipient. See What “sent” means.
Draft	The mail is saved in the Drafts folder. Only with Client: Outlook.

The new Outlook

The new Outlook for Windows cannot be controlled by any program. Send through Microsoft 365 instead.

With Default or the name of another program RUNOS uses the Windows “Simple MAPI” interface. It knows only plain text and fewer options: RUNOS converts HTML to text and leaves out ReplyTo, Importance, DeliveryReceipt, OutlookSignature and From; every omitted option is a warning in the result (for OutlookSignature only the value Always). In the form these options are marked Outlook only.

You have …	Use
credentials for an SMTP server	SMTP
classic Outlook and want to check mails before sending	MAPI with Client: Outlook and Mode: Display
Thunderbird, eM Client, Tobit David or another mail program	MAPI with Client: Default or the program’s name
Microsoft 365 / the new Outlook, or no mail program	Microsoft 365

32-bit mail programs

RUNOS is a 64-bit program. Some mail programs, such as Tobit David (Team), exist only as 32-bit programs; their MAPI interface cannot be loaded into RUNOS directly. For them RUNOS starts a small 32-bit mail helper, which hands the mail to the program and reports its answer back. There is nothing to set up: RUNOS detects when sending whether a program is 32- or 64-bit. This also applies to Default when the default mail program is a 32-bit program.

The helper is part of RUNOS and is unpacked to %LOCALAPPDATA%\RUNOS\MapiHost32\ the first time it is needed. Before each use RUNOS compares the file with its own copy; a changed file is replaced, never started. If security software or an AppLocker policy blocks programs in that folder, the action says so; allow RUNOS.MapiHost32.exe there. Mail programs installed only as ARM64 programs cannot be used by RUNOS.

Signature

A mail gets one signature at most: the one from the Signatur field or the Outlook signature of the sending account, never both. The text from Body is always at the top, the signature below it.

With classic Outlook, OutlookSignature decides (in the form: Outlook signature under More options):

OutlookSignature	Signatur empty	Signatur filled in
Auto (default)	text, below it the Outlook signature	text, below it only Signatur; no Outlook signature
Always	text, below it the Outlook signature	text, below it the Outlook signature; Signatur is left out, with a warning
Never	only the text	text, below it Signatur

If the account has no default signature for new messages in Outlook, the mail holds just the text. With the Outlook signature the mail is created as HTML, unless BodyFormat is Text.

With every other mail program (Default, Thunderbird, eM Client, Tobit David …) RUNOS only adds Signatur below the text. Whether the program adds a signature of its own is up to the program; RUNOS can neither read nor remove it. If you use Signatur, turn the signature off in the mail program so the mail does not get two.

Workflows from earlier versions keep running: true counts as Always, false as Never. Without the parameter, Auto applies. Until now a missing value meant no Outlook signature; check such workflows if the mail should stay without a signature, and set Never there.

What “sent” means

RUNOS reports Sent only when the mail program confirms that it took the mail. What happens next is up to the mail program: it sends right away, or keeps the mail in its outbox until it is online. If it refuses the mail or reports an error, the action fails and the mail does not count as sent.

• Classic Outlook: if Outlook was not running before, RUNOS waits up to Timeout seconds for the Outbox to empty; if the mail is still there, the result has a warning.
• Other mail programs: some still show a window or ask before sending, even with Send. If you close it without sending, the Status is Cancelled. Whether a program sends without asking is decided by the program, not by RUNOS; try it once with a test mail.

Structure

{
  "Type": "MAPI",
  "Name": "CreateMail",
  "Parameters": {
    "Client": "Outlook",
    "Mode": "Display",
    "To": "{{InitialData.Recipient}}",
    "Subject": "Your documents from %DATE%",
    "Body": "Hello,\n\nplease find the requested documents attached.",
    "Attachments": "C:\\RUNOS\\Out\\*.pdf",
    "MissingAttachments": "Error"
  }
}

Parameter	Default	Meaning
Client	Default	Default, Outlook or the name of a mail program, see above
Mode	Display	Display, Send or Draft, see above. Any other value fails the action.
Profile	–	Outlook profile (Outlook only)
From	–	Outlook only: account or shared mailbox to send from
To, Cc, Bcc	–	Recipients separated by ; or ,. Name <a@b.com>, a list or the path of a file with addresses.
ReplyTo	–	Reply address (Outlook only)
Subject	–	Subject
Body	–	Text or path of a text or HTML file
Signatur	–	Text or path of a text or HTML file, placed below the text. With OutlookSignature: Auto it replaces the Outlook signature, see Signature.
BodyFormat	Auto	Auto, Html or Text. Auto uses HTML when the text or signature contains HTML tags.
OutlookSignature	Auto	Auto, Always or Never: when the sending account’s Outlook signature goes below the text (Outlook only), see Signature
Attachments	–	One path, several separated by ; or line breaks, a list or a pattern such as C:\Out\*.pdf
MissingAttachments	Error	Error: a missing attachment makes the action fail. Skip: send without it, with a warning.
Importance	Normal	Low, Normal, High (Outlook only)
ReadReceipt	false	Request a read receipt
DeliveryReceipt	false	Request a delivery receipt (Outlook only)
Timeout	60	Seconds RUNOS waits for Outlook to send if Outlook wasn’t running before

All values may contain placeholders, yes/no values too ("true", "yes", "1"). The older parameters DisplayBeforeSend, HighImportance and IsHtml keep working.

Result

"Response": {
  "Results": [
    {
      "Client": "Team",
      "Program": "Team",
      "Mode": "Send",
      "Status": "Sent",
      "To": "customer@example.com",
      "Cc": "", "Bcc": "",
      "Subject": "Your documents from 2026-10-08",
      "Attachments": [ "C:\\RUNOS\\Out\\offer.pdf" ],
      "Message": "Team confirmed the mail and sends it (it may wait in its outbox until it is online)."
    }
  ],
  "SuccessCount": 1,
  "ErrorCount": 0
}

Status is Sent (taken by the mail program), Displayed, Saved (draft), Cancelled (opened or asked, and closed without sending) or Error. Program is the mail program that took the mail (with Default, the default mail program; missing with Client: Outlook). Message describes the result, followed by all warnings.

Error messages

Message	What to do
Mode "…" is not valid. Use one of: Display, Send, Draft.	Set Mode to one of these values; in the form under What happens.
Mail program "…" is not installed for MAPI on this PC. Installed: …	Use one of the names listed as Client, or install the program.
No default mail program is set in Windows.	Set a default mail program in Windows, or choose a program under Client.
The MAPI component of … is missing or … or a file it needs is missing	Repair or reinstall the mail program.
… the 32-bit mail helper, which could not be started	Allow RUNOS.MapiHost32.exe in %LOCALAPPDATA%\RUNOS\MapiHost32\ in the security software or AppLocker.
…: logon to the mail program failed (is an account set up?) (MAPI error 3). The mail was not sent.	Set up an account in the mail program or sign in. Other MAPI errors name their reason the same way.
OutlookSignature "…" is not valid. Use one of: Auto, Always, Never.	Set OutlookSignature to one of these values, in the form via Outlook signature.
Mode "Draft" works only with Client "Outlook".	Use Client: Outlook, or Display or Send.

Example

Save every PDF from the folder C:\RUNOS\Offers as a draft in classic Outlook, from the shared mailbox sales@example.com. As Signatur is not set, the Outlook signature goes below the text:

{
  "Name": "Offers as drafts",
  "Autostart": true,
  "Trigger": { "Type": "File", "Name": "Offers", "Parameters": { "Pool": "C:\\RUNOS\\Offers", "Filter": "*.pdf" } },
  "Actions": [
    {
      "Type": "MAPI",
      "Name": "Draft",
      "Parameters": {
        "Client": "Outlook",
        "Mode": "Draft",
        "From": "sales@example.com",
        "To": "{{InitialData.Customer}}",
        "Subject": "Your offer {{FileName}}",
        "Body": "C:\\RUNOS\\Templates\\offer.html",
        "Attachments": "{{FilePath}}",
        "Importance": "High"
      }
    }
  ]
}

The recipient comes from the PDF by script block: #RUNOS InitialData.Customer=customer@example.com #RUNOS.